As a method for growing a high quality semiconductor film, there is an epitaxial growth technique in which a single crystal film is grown on a wafer (substrate) by vapor phase growth.
In the film growth method and the film growth apparatus using this epitaxial growth technique, the wafer is heated while being supported by a supporter in a reactor maintained under normal pressure or reduced pressure. Next, a reactant gas as a source of film formation is supplied onto the wafer. A thermal reaction, or the like, of the reactant gas occurs on the surface of the wafer, leading to formation of an epitaxial single crystal film.
In particular, exhaust gas after film formation by metal organic chemical vapor deposition (MOCVD) contains a large amount of reaction byproducts. These reaction byproducts are deposited inside a valve provided for pressure adjustment of the reactor and are turned into a residue. The residue causes biting between a valving element and a valve box, leading to a difficulty in operation of the valving element. This would produce a necessity of cleaning the valve, decreasing an availability of the film growth apparatus.
As described above, there is a problem of the decrease in availability of the film growth apparatus due to the residues caused by reaction byproducts. This problem becomes significant particularly by controlling a plurality of reactors to have a same condition and unifying an exhaust system in processing a plurality of wafers in parallel in order to increase throughput.